Lianja

Verify JWT Using an RSA Public Key (RS256, RS384, RS512)

Demonstrates how to verify a JWT that was signed using an RSA private key.

This example verifies the RSA signature. It also does the following:

Checks to see if the time constraints ("nbf" and "exp") are valid.
Recovers the original JOSE header.
Recovers the original claims JSON.

Chilkat Lianja Downloads

Lianja

llSuccess = .F.

// Demonstrates how to verify an JWT using an RSA public key.

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

loPubKey = createobject("CkPublicKey")
llSuccess = loPubKey.LoadFromFile("qa_data/pem/rsa_public.pem")

loJwt = createobject("CkJwt")

lcToken = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDQ1MjM4LCJuYmYiOjE0NjM0NDUyMzgsImV4cCI6MTQ2MzQ0ODgzOH0.XRtqed6nuJ9lrp0wbNdDX3fCkSh_d9cHAniPbNcqm7G-5N3mtI5ntQvZBDP3pHtECVqufuDwW7XgUtzAi0ZXhyiRm1iZ3wMSN5lHWv52OQJmMHPA7VPd8Q1hDG-tx-QswzJKd75OEUHP7wIXq2Mg_YVElfDvJI6TGjGyS1y-RLHlz-ldlGsEwIBkO0PtzIYTVov97x8p9KCsPNhS4lZUIqKOYoTZUV5LpuAWARl-636DfMEB_A5_IEaw_W8leh2suP2ULVZxwE-Tk1kBC9tsSGrBrPTtg7sziaV4Lbb0JRANmh98uTRu5f8ji9CVOnpbMiAzjsJSy56kz_olweXSuA"

// First verify the signature.
llSigVerified = loJwt.VerifyJwtPk(lcToken,loPubKey)
? "verified: " + str(llSigVerified)

// Let's see if the time constraints, if any, are valid.
// The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
// If the current system time is before the "nbf" time, or after the "exp" time,
// then IsTimeValid will return false/0.
// Also, we'll allow a leeway of 60 seconds to account for any clock skew.
// Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
lnLeeway = 60
llBTimeValid = loJwt.IsTimeValid(lcToken,lnLeeway)
? "time constraints valid: " + str(llBTimeValid)

// Now let's recover the original claims JSON (the payload).
lcPayload = loJwt.GetPayload(lcToken)
// The payload will likely be in compact form:
? lcPayload

// We can format for human viewing by loading it into Chilkat's JSON object
// and emit.
loJson = createobject("CkJsonObject")
llSuccess = loJson.Load(lcPayload)
loJson.EmitCompact = .F.
? loJson.Emit()

// We can recover the original JOSE header in the same way:
lcJoseHeader = loJwt.GetHeader(lcToken)
// The payload will likely be in compact form:
? lcJoseHeader

// We can format for human viewing by loading it into Chilkat's JSON object
// and emit.
llSuccess = loJson.Load(lcJoseHeader)
loJson.EmitCompact = .F.
? loJson.Emit()


release loPubKey
release loJwt
release loJson